Bivalved cast

ABSTRACT

A cast for immobilizing broken limbs which includes a pair of bivalved shells, an inflatable liner in each of the shells, an absorbent liner or padding, and means for releasably securing the bivalved shells together. The cast is reuseable, permits convenient visual inspection of the broken limb without destruction of the cast, and provides for adjustment of the volume of the inside cavity and the pressure on the immobilized limb through adjustment of the inflatable liners.

United States Patent Leighton W. Larson P. 0. Box 202, Waoonia, Minn.55387 21 Appl. No. 780,335

[22] Filed Dec. 2, 1968 [45] Patented May 25, 1971 [72] Inventor [54]BLVALVED CAST 8 Claims, 4 Drawing Figs.

[52] U.S. Cl 128/89 [51] Int. CL A6lf 5/04 [50] Field ofSearch 128/87,88, 89, 90, 165, (Inflatable Splint Digest), 83, 83.5, 84-86, 297, 30.2,298

[56] References Cited UNITED STATES PATENTS 3,032,033 4/1970 Ramirez3,351,055 11/1967 Gottfried 128/87 Primary Examiner-Richard A. GaudetAssistant Examiner-J. B. Mitchell Attorneys-Frederick E. Lange, John J.Held, Jr. and Eugene L. Johnson ABSTRACT: A cast for immobilizing brokenlimbs which includes a pair of bivalved shells, an inflatable liner ineach of the shells, an absorbent liner or padding, and means forreleasably securing the bivalved shells together. The cast is reuseable,permits convenient visual inspection of the broken limb withoutdestruction of the cast, and provides for adjustment of the volume ofthe inside cavity and the pressure on the immobilized limb throughadjustment of the inflatable liners.

Patented May 25, 1971 3,580,248

T1 4 z av WMes'm/ S BI-VALVED CAST BACKGROUND OF THE INVENTION Theinvention relates to the field of immobilizing broken limbs and otherbody parts through the use of a cast or splint. The customary means ofimmobilizing a broken limb is the plaster-of-paris cast which is notreuseable, does not provide for visual access without the destructionthereof, and which cannot be adjusted to compensate for swelling andcontraction of the immobilized limb.

There have been a number of efforts to depart from the traditionalplaster-of-paris cast in favor of a lighter, reuseable and adjustablecast. There have also been efforts to make casts which may open forvisual inspection of the limb, and close when the inspection iscompleted. None of these prior art devices, however, offer theadvantages of the present invention.

The Ramirez patent US. Pat. No. 3,032,033, for example, discloses aresin-impregnated fiberglass shell which includes two halves which aresecured together to form a cast which conforms to the shape of the limbto be immobilized. The

Ramirez cast, however, does not include any means for adjusting orcompensating for the difference in configuration between the limb andthe shell of the cast. In other words, the rigid shell portion must beformed with extreme care to insure that it conforms accurately to theshape of the limb which is to be immobilized. The present invention,with its inflatable liner, provides for substantial adjustment to insurethat the immobilized limb will be tightly held even though there may bedifferences in shape and size between the cast and the limb. Moreover,the present invention allows for continued adjustment to compensate forswelling or a decrease in size of the immobilized limb.

The Gottfried patent (US. Pat. No. 3,153,413) discloses an inflatablepressure bandage-splint which provides adjustability to compensate forswelling or decrease in size but it does not include a rigid outerprotective shell. In addition the Gottfried bandage-splint provides forvisual access and reclosing of the device. There is, however, a lack inuniformity in the thickness of the inflatable liner from a maximumthickness opposite the closure means to a complete lack of thickness atthe closure means. The lack in liner thickness at the closure meansalong with the lack of a protective rigid outer shell limits the valueof the Gottfried design to temporary or first-aid type applications.

Other substances have been disclosed for use in the formation of a castsuch as plastic foam which is the subject of the Gibbons patent (US.Pat. No. 3,403,676). Although initially there is excellent conformancebetween the cast and the immobilized limb, the Gibbons splint does notinclude any means for adjusting the inside cavity of the splint as theimmobilized limb swells or decreases in size.

SUMMARY The present invention provides a bivalved cast which overcomesmost of the problems of the prior art. The invention includes two rigidhalf shells which correspond generally to the body portion to beimmobilized and which each have a generally channel-shaped cross sectionand mating edges which define a plane passing through the longitudinalaxis of the body portion. An inflatable liner is disposed in each of therigid shells and extends over substantially the entire inner surface.Means is provided exterior of the rigid shells for inflating each of theliners. A layer of absorbent material is placed inwardly of the linersto make direct contact with the immobilized limb. Means is provided forreleasably joining the two shells to thereby form a protective castwhich may be opened for visual access to the limb.

In addition to the provision of convenient visual access withoutdestruction of the cast, the present invention makes adjustment of thecast a simple matter. More particularly, as the limb swells or contractsthe pressure in the inflatable liners may be varied to compensate forthe swelling or contraction and the thereby maintain a constant pressureon the limb. Moreover, pressure may be varied, within the limitsnecessary to immobilize the limb, to provide for individual patientcomfort.

The bivalved cast of the present invention need not be formed toaccurately conform to the shape of the body portion which is to beimmobilized, since discrepancies may be readily compensated for by theinflatable liners. And finally the cast of the present invention issubstantially lighter than most casts, particularly the plaster-of-pariscast, yet provides equivalent protective and immobilization strength.

The primary object of the present invention is to provide a reuseablecast which may be opened for visual access to the immobilized limbwithout destruction of the cast and which includes means for adjustingthe pressure between the cast and the limb.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of thebivalved cast which comprises the present invention, in its closedposition, without association with the limb to be immobilized. While acast for the lower leg is shown, the present invention may be used for anumber of other applications. In FIG. 1 the inflatable liner andabsorbent material may be seen as well as one connection for inflatingthe liner.

FIG. 2 is a sectional view of the cast shown in FIG. 1 and shows theupper and lower shell, the upper and lower inflatable liners, theabsorbent padding material placed inwardly of the inflatable liner, anda sectional view of the immobilized limb, in this case a leg. FIG. 2also shows the means for releasably securing the two rigid shellstogether.

FIG. 3 is an enlarged sectional view of the means for releasablysecuring the two shell halves together.

FIG. 4 is an axial sectional view of the cast and shows the relationshipbetween the cast, the inflatable liners, the absorbent padding material,and the immobilized limb.

DESCRIPTION OF THE PREFERRED EMBODIMENT The general nature of thepreferred embodiment may be readily understood with reference to FIG. 1.The bivalved cast 10 which comprises the present invention includes anupper rigid shell 11 and a lower rigid shell 12. Both shells l1 and 12are formed to conform to the general shape of the body portion which isto be immobilized, in this case a leg, and each of the shells have agenerally channel-shaped cross section. Each of the shells has two edgesextending longitudinally thereof and which define a plane passinggenerally throughthe longitudinal axis of the immobilized limb. Withreference to FIG. 1 the edges are shown in mated relationship at 13 and14. Thus the edges (the point of contact between the upper rigid shell11 and the lower rigid shell 12) define a plane passing through thelongitudinal axis of the immobilized limb.

Each of the shells is provided with an inflatable liner. Liner 15 isnested in rigid shell 11 and liner 16 is nested in rigid shell 12. Eachof the inflatable liners 15 and 16 extend over substantially the entireinner surface of rigid shells 11 and 12, respectively.

Valve 20 protrudes from rigid shell 11 to serve as a means for inflatingliner 15. A similar valve 21 protrudes from lower rigid shell 12 toserve inflatable liner 16, as best seen in FIG. 2.

A layer of absorbent material such as sheet wadding 22 and 23 is placedinwardly of inflatable liners 15 and 16, respectively, to make directcontact with the immobilized limb.

The means for releasably securing the rigid shells 11 and 12 is matedrelationship, as shown in FIGS. 1 and 2, includes a pair of fasteners oneach side of each shell. Each fastener includes a bracket 25 secured toupper rigid shell 11 such as by rivets 26, most conveniently seen inFIG. 3. A lower bracket 27 is secured to lower shell 12 such as byrivets 28. Threaded member 29 is pivotally secured to lower bracket 27and passes through bracket 25 to accept wingnut 30 which is threadedthereto. Bracket 25 is offset downwardly with respect to joint of thelower leg from a point above the knee to a point below the heel, thebivalved cast which comprises the present invention may be used for awide variety of other applications. More particularly, it may be formedwith a rigid shell conforming in shape to other parts of the body sothat it may be used for fractures of the calcaneus, matetarsals,fibulas, tibias, femur, fractures of the body of vertabres, fractures ofvertrabral bodies, clavicular fractures, metacarpal fractures, etc. Itis therefore contemplated that the present invention may be used as anupper leg cast, lower leg cast, an upper arm cast, a lower arm cast, abody spica, a foot cast, a neck cast, and a hand cast.

Rigid shells 11 and 12 may be formed in a wide variety of substances,the primary requirements being radiolucence and adequate rigiditywithout excessive weight. Substances such as aluminum, resin-impregnatedfiberglass and plastics may be used. Suitable commercial substances aresold under the trademarks GLASKYD, available commercially from AmercianCyanamid Company, SCOTCHPLY, available commercially from 3M Company,BAKELITE, available commercially from Union Carbide Plastics Company andDUREZ, available commercially from Hooker Chemical corporation, DurezPlastics Division.

Inflatable liners l and 16 may be formed of rubber, plastic or otherpliable material which is inflatable.

The absorbent layers of absorbent material 22 and 23 placed inwardly ofinflatable liners l5 and 16 may be formed of gauze or sheet wadding or asponge material.

Other means may be employed to releasably secure the two rigid shellstogether. A wide variety of fasteners may be used including thenonmetallic fastener sold under the trademark VELCRO, a productavailable commercially which consists of mating hooked pile fabricforces.

The pressure in inflatable liners l5 and 16 should be 75 to 95 percentof diastolic pressure for best results. Such a pres sure range providessubstantial immobilization of the body portion and yet does not inhibitor prevent circulation of blood in the arteries and veins of the bodyportion in the cast.

The operation of the present invention may be readily understood withreference primarily to H65. 1 and 2. The rigid shells 11 and 12 areopened and the limb, L, is placed in the lower shell 12 and the uppershell 11 is closed. After shells 11 and l2are secured in matedrelationship, air is introduced into inflatable liners l5 and 16 throughconnections and 21. A conventional pressure device may be readilyemployed to measure the pressure in the liners. Liners l5 and l6 providea uniform pressure on the immobilized limb and automatically compensatefor any variation in distance between the shell and the limb such as maybe seen with reference to FIG. 4. As

the limb swells or contracts the volume of air in liners 15 and 16 maybe varied to maintain the limb under a constant pressure.

The cast may be opened to allow visual inspection of the limb withoutdestroying the cast. When inspection and treatment is complete is may beconveniently closed.

The bivalved cast 10 may be reused by simply removing the layers 22 and23 of absorbent material followed by replacement with new material. Thecast may also be washed if desired.

In conclusion, it may be seen that the present invention provides anovel bivalved cast which has significant advantages over the casts ofthe prior art.

Variations may be made in the form of the invention shown withoutdeparting from its scope which is to be limited only by the followingclaims.

I claim: l. A bivalved cast comprising:

a first and second rigid shell corresponding in configuration to thebody portion to be immobilized, each of said shells having a generallychanneled-shaped cross section and mating edges which define a planepassing through the longitudinal axis of said body portion;

first and second inflatable liner disposed in said first and secondrigid shells, respectively, and extending over substantially the entireinner surface thereof;

first and second means exterior of said first and second rigid shellsfor introducing air into said first and second inflatable liners,respectively;

a first and second layer of absorbent material adapted to engage saidbody portion disposed inwardly of said first and second inflatableliners, respectively; and

means releasably joining said first and second rigid shells at saidmating edges to thereby form a cast conforming in configuration to saidbody portion.

2. The cast of claim 1 wherein said first and second inflatable linersconfine air under pressure in the range of 75 to percent of diastolicpressure.

3. The cast of claim 2 wherein said mating edges on one side of saidrigid shells are hinged together to thereby allow opening of one of saidrigid shells with respect to the other for visual access to said bodyportion Without destruction of said cast.

4. The cast of claim 3 wherein said first and second rigid shells areformed of rigid plastic material.

5. The cast of claim 4 and means for preventing lateral movement of saidfirst rigid shell with respect to said second rigid shell when saidshells are secured in mating relationship.

6. The cast of claim 5 wherein said first and second inflatable linersare adhesively secured to said first and second rigid shells,respectively.

7. The cast of claim 6 wherein said first and second layer of absorbentmaterial is adhesively secured to said first and second inflatableliners, respectively.

8. The cast of claim 7 and check valve means for allowing introductionof air into said liners and preventing deflation thereof.

1. A bivalved cast comprising: a first and second rigid shellcorresponding in configuration to the body portion to be immobilized,each of said shells having a generally channeled-shaped cross sectionand mating edges which define a plane passing through the longitudinalaxis of said body portion; first and second inflatable liner disposed insaid first and second rigid shells, respectively, and extending oversubstantially the entire inner surface thereof; first and second meansexterior of said first and second rigid shells for introducing air intosaid first and second inflatable liners, respectively; a first andsecond layer of absorbent material adapted to engage said body portiondisposed inwardly of said first and second inflatable liners,respectively; and means releasably joining said first and second rigidshells at said mating edges to thereby form a cast conforming inconfiguration to said body portion.
 2. The cast of claim 1 wherein saidfirst and second inflatable liners confine air under pressure in therange of 75 to 95 percent of diastolic pressure.
 3. The cast of claim 2wherein said mating edges on one side of said rigid shells are hingedtogether to thereby allow opening of one of said rigid shells withrespect to the other for visual access to said body portion withoutdestruction of said cast.
 4. The cast of claim 3 wherein said first andsecond rigid shells are formed of rigid plastic material.
 5. The cast ofclaim 4 and means for preventing lateral movement of said first rigidshell with respect to said second rigid shell when said shells aresecured in mating relationship.
 6. The cast of claim 5 wherein saidfirst and second inflatable liners are adhesively secured to said firstand second rigid shells, respectively.
 7. The cast of claim 6 whereinsaid first and second layer of absorbent material is adhesively securedto said first and second inflatable liners, respectively.
 8. The cast ofclaim 7 and check valve means for allowing introduction of air into saidliners and preventing deflation thereof.